RFL Electronics GARD 8000 - Sequence of Events and Oscillogra Phy

Current Differential Relay
GARD 8000 SYS RFL Electronics
June 20, 2014 13-78 973.334.3100
13.6 SEQUENCE OF EVENTS AND OSCILLOGRAPHY
13.6.1 SOE
The relay has a sequence of events recorder (SOE) which can be configured to store information based
upon user selectable triggers. The data saved is an instantaneous “snapshot” of the conditions when the
trigger event occurred. This differs from the oscillography records which records the data over a
period of time around the trigger event.
The user can select various parameters to trigger (initiate) an SOE recording. Any change of a trigger
(becoming active or inactive) will initiate a recording. Trip outputs are automatically enabled as
triggers and cannot be disabled by the user.
13.6.2 OSCILLOGRAPHY
The relay includes an oscillography recording function that allows the conditions surrounding a trip to
be captured for later review. The recording includes the measured currents and a large amount of
status information regarding the system conditions and relay calculations.
13.6.2.1 LENGTH OF OSCILLOGRAPHIC RECORD
The user can select the length of the oscillography recordings between 10 and 180 cycles. The length
selected for each recording can impact the maximum number of recordings the relay can store due to
the finite memory available. All of the oscillography recordings saved in the relay must have the same
configuration, therefore, if the user changes the oscillography length setting all previously recorded
oscillography records will be erased.
13.6.2.2 PRE-TRIGGER LENGTH
The user can select the amount of pre-trigger information retained in the oscillography recordings
between 0 and 180 cycles. If the length selected exceeds the user setting for the total recording length
(section 13.6.2.1) the relay will use the selected recording length setting and set the entire recording as
pre-trigger data. All of the oscillography recordings saved in the relay must have the same
configuration, therefore, if the user changes the pre-trigger length setting all previously recorded
oscillography records will be erased.
13.6.2.3 NUMBER OF OSCILLOGRAPHY RECORDINGS
A maximum of approximately 2300 cycles can be recorded in the memory. The number of fault
records depends on the length selected for the recording. Maximum number of records is 64, if more
than 36 cycles are recorded per record the maximum number of records will be less than 64.
Table 13-2 shows the rough correspondence between record length and number of records.